the 717 doesnt get a good write-up in relation to the valve units and they do have a point.etherical and light as somebody said transistorised ect.when staxs troubles started some years ago so did mine stopped working.On removing the cover in a minute I discovered that the mains input fuse had blown(600ma) I replaced it with a 1amp fuse after testing it by shorting out one leg of each full wave rectifiersin turn(blew every time). The transformer is high quality as is the volume control and electrolytic capacitors.But I was not so pleased with some of the active devices The input fets had a small plastic cap on them removing it revealed two cheap fets pressed together(thermal equality) .removing the other two(bjt)transistors plastic cap revealed two cheap low noise bjts /.The high voltage bjts (not the output devices) were the bottom of the range in a range of three.ALL the bjts that heated up were without heatsinks(on the daughter boards).The more heat the more noise. even if you do not hear it due to the low sensitivity it affects low level reproduction.The ac ripple was 140ma not good for something costing a lot of money.The low voltage(+-) 15 volts had only one pair of voltage regulators for both channels.not to good for o/h and there is more but my wife is shouting at me toget my dinner.ifhead-fi will allow I will carry on in another review(thats if you want me to.